Observations of Impulsive Electric Fields Induced by Interplanetary Shock. Issue 15 (8th August 2018)

• Record Type: Journal Article
• Authors: Zhang, Dianjun; Liu, Wenlong; Li, Xinlin; Sarris, Theodore; Xiao, Chao; Wygant, J. R.
• Is Part Of: Geophysical research letters. Volume 45:Issue 15(2018)
• Page Start: 7287
• Page End: 7296
• Publication Date: 2018-08-08
• Subjects: electric field -- interplanetary shock -- inner magnetosphere -- particle acceleration; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2018GL078809
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We investigate the characteristics of impulsive electric fields in the Earth's magnetosphere, as measured by the Van Allen Probes, in association with interplanetary shocks, as measured by Advanced Composition Explorer and Wind spacecraft in the solar wind from January 2013 to July 2016. It is shown that electric field impulses are mainly induced by global compressions by the shocks, mostly in the azimuthal direction, and the amplitudes of the initial electric field impulses are positively correlated with the rate of increase of the dynamic pressure across the shock in the dayside. It is also shown that the temporal profile of the impulse is related to the temporal profile of the solar wind dynamic pressure, P d . It is suggested that during the first period of the impulse, the evolution of the electric field is directly controlled by external solar wind forcing, and thus, finite rates of change of P d should be considered in the study of the interactions between solar wind and magnetosphere. The implications of shock‐induced impulsive electric fields on the acceleration and transport of radiation belt electrons are also discussed. Plain Language Summary: When an interplanetary shock hits the Earth's magnetosphere, it can cause a series of changes of the Earth's magnetosphere due to the sudden compression on the Earth's magnetic field. One of the important consequences is the impulsive electric field induced by the magnetic field compression, which can lead to particle acceleration and enhanced transport. This paper studies the characteristic of the impulsive electric field, especially on the amplitude and evolution during the first impulse after shock arrival. It is shown that the first period of the impulse is directly controlled by external solar wind forcing. The results are important for understanding the mechanism of shock‐related phenomena in the inner magnetosphere. Key Points: Impulsive electric field induced by interplanetary shock is studied based on Van Allen Probes measurements The amplitudes of the initial impulses in the dayside are positively correlated with the sudden increase of dynamic pressure of the shock The evolution of the first period of the impulse is directly controlled by external solar wind forcing